The present invention relates to the field of user terminals in general, and more particularly, to input to user terminals.
Some user terminals, such as radiotelephones, include a cover which is moveably coupled to the user terminal. For example, a cover of a radiotelephone can be moveably coupled to the radiotelephone by a hinge wherein the cover can be closed while the radiotelephone is inoperative and open while the radiotelephone is in use.
It is known to include components in the cover, wherein the components may provide input to the user terminal. For example, some radiotelephones include a microphone in the cover so that when the cover is open the microphone can be positioned near the user""s mouth. Conductors may be used to carry the input from the components in the cover through the moveable coupling to the user terminal housing. Unfortunately, if additional input devices are provided on the cover of the user terminal, it may be difficult to route the conductors from the cover to the user terminal. For example, it may be difficult to route multiple conductors from the cover to the user terminal via a hinge that connects the cover to the user terminal. Consequently, a need exists for user terminals having improved structures and methods to provide input to the user terminal from movable covers.
It is, therefore, an object of the present invention to allow user terminals having improved input thereto.
It is another object of the present invention to allow a reduction in a number of conductors used to provide input to user terminals.
These and other objects of the present invention can be provide by user terminals that include a conductor that conducts electrical signals. A first input device is electrically coupled to a conductor, and the first input device applies an AC signal to the conductor in response to input thereto. A second input device is electrically coupled to the conductor, and the second input device applies one of a plurality of DC signals to the conductor in response to input thereto. An AC coupler circuit is coupled to the conductor. A DC detector circuit is coupled to the conductor, and the DC detector circuit determines the DC signal level generated by the second input device. Accordingly, coupling for a plurality of input devices can be provided through a common conductor. In one embodiment, the first input device can be a microphone, and the second input device can be a handwriting pad.
In a further aspect of the present invention, the user terminal can include a user terminal housing, wherein the AC coupler and the DC detector are housed within the user terminal housing and a cover housing, moveably coupled to the user terminal housing, wherein the first and second input devices are housed within the cover housing. By coupling the first and second input devices in the cover through a common conductor, a number of conductors between the cover and the housing can be reduced.
Accordingly, AC and DC signals can be applied to a first conductor as a result of respective first and second inputs. The AC and DC signals are provided to the AC coupler circuit and DC detector, respectively. The AC coupler circuit and DC detector can determine the inputs based on determinations from the combined signal on the first conductor. Accordingly, the number of conductors needed to carry the inputs from a cover housing to the radiotelephone housing may be reduced. In particular, methods and systems according to the present invention can be used advantageously in radiotelephones including flip covers.